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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
NASA NTRS2024

Mechanical Testing of Soils from the South Range of the Utah Test and Training Range: Derivation of Soil Properties to Support the Earth Entry System Landing for Mars Sample Return

This report summarizes results from laboratory tests conducted by Applied Research Associates, Inc. (ARA) on soil samples collected from multiple sites within the South Range of the U.S. Air Force Utah Test and Training Range (UTTR). The goal of the laboratory tests was to establish soil constitutive properties and develop computational soil models enabling NASA to simulate impact landings of the Earth Entry System (EES) for the Mars Sample Return (MSR) mission. Test methods and results are presented describing the strength, compressibility, and stiffness of soils in the UTTR South Range including methods to incorporate the measured properties into Ansys LS-DYNAÒ constitutive material models for EES landing simulations.

Soil↗
DOE OSTI2020

Advanced Self-Healing Polymer-Cement Composites for Geothermal Wellbore Application at 300 °C

Polymer-cement composites were formulated using two base cements and three polymers and evaluated as potential alternatives to conventional geothermal wellbore cementitious material. To mimic geothermal conditions these cement composites were cured at 300 °C and their mechanical properties, including compressive strength, Young modulus, shear bond strength to steel casing, and self-healing and re-adhering (to steel) capability were tested. To test thermal stability the samples were cured at 300 °C for up to 30 days followed by analysis of their mineralogy and chemical composition by X-ray diffraction spectroscopy (XRD), 13C NMR, and total organic carbon (TOC). These tests showed that all polymer composites formulated were thermally stable as supported by almost 100% TOC of the 300 ?C cured samples and presence of all the polymer signals in 13C NMR permeability tests performed before and after healing a longitudinal fracture base cements and polymer-cement composites gave lower (2nd/1st) permeability ratios with respect to base cements which suggests that introduction polymers result in self-healing composite materials. Curing two of the best performing polymer-cement composites for a period of 30 days at 300 °C maintained the self-healing capability. These advanced polymer-cement composites with higher mechanical stability, ductility and self-healing capability are promising alternatives to wellbore cement materials for geothermal and fossil energy applications.

polymer-cement, composite, wellbore, self-healing,↗
DOE OSTI2021

Developing a Drilling Optimization System for Improved Overall Rate of Penetration in Geothermal Wells

Geothermal energy is renewable, reliable and environmentally friendly source of energy. The major cost in the development of geothermal wells is the actual drilling of the wells. The main objective of this paper is to introduce a new real-time drilling optimization system designed for granite formation to reduce the overall drilling cost. In this study, a drilling optimization system is verified using drilling data from Utah-Forge well 58-32. The drilling optimization system used the Utah-Forge well 58-32 data to achieve real-time unconfined compressive strength (UCS). Based on the UCS value from the previous feet, the system simulates the ROP for the next drilling feet. The drilling optimization system utilizes the Differential Evolution Algorithm (DEA), which is a metaheuristic method to search the space of solution, to find the best operating parameters (i.e. WOB and RPM) for the next drilling foot. The optimization algorithm takes a maximum cutter temperature into account as a constraint and avoids the accelerated wear. The developed drilling optimization system improves ROP responses and reduces the drilling cost of geothermal wells. The simulated ROP results from the system show a good agreement with the ROP from Utah-Forge well 58-32 drilling data. The drilling time before and after optimization for both intervals were presented.

15 GEOTHERMAL ENERGY↗
DOE OSTI2022

DEVELOPMENT OF AN APPROACH FOR DOWNBLENDING AND DISPOSITION OF IRRADIATED GRAPHITE FUEL

The IGR reactor, a pulse-type test experimental reactor, reached full power in 1961. The reactor contains a center axial experimental ampoule that is subjected to a large pulse of neutrons (neutron flux maximum density of 7×1016 n/cm2·s, peak power 10GW) when the reactor is operated. The fuel form for the IGR reactor is graphite cubes and rods impregnated with highly enriched (90%) uranyl-dinitrate (UO2(NO3)2·6H2O). This fuel is eligible for return to Russia for reprocessing under the Russian Research Reactor Fuel Return program. However due to some technical and licensing issues it was decided to immobilize this fuel in Kazakhstan. The disposition approach thus selected for the spent HEU fuel involves down-blending of the fuel followed by cementation. Development of the process for down-blending and subsequent cementation requires a process that satisfies many criteria, including fissile content, compressive strength, permeability, and containment of radioactivity, among others. One key goal of the final product is to meet the criteria for termination of safeguards. This paper will describe the overall challenge associated with disposition of irradiated HEU graphite spent fuel, the identification of the objectives of the disposition process, and the constraints associated with development of the process and the waste form.

Gaines, Kris↗
DOE OSTI2018

Immobilization of Organic Liquid Radioactive Waste (LWR) in a Sulfur Composite Matrix at the BN-350 Fast Neutron Reactor Site, Kazakhstan - 18031

The immobilization treatment and final disposition of all forms of organic radioactive liquids, such as pump oil, spent solvent, tri-butyl-phosphate (TBP) and scintillation fluids, remain a significant challenge for nuclear waste generators and national regulators. The majority of nuclear nations have instituted regulations that require some form of encapsulation of treated organic liquid, notwithstanding LLW organic liquids that can be safely incinerated. In most cases cement is the designated material for encapsulation; however, cement can pose certain problems with the containment of treated organic liquids. In 2013, with funding from the U.S. Department of Energy - National Nuclear Security Administration through its Global Initiative for Proliferation Prevention Program (GIPP), a proven U.S. technology for the treatment of radioactive organic liquids was introduced at the BN-350 fast neutron reactor facility in Aktau, Kazakhstan. As the facility was undergoing full decommissioning, one hundred and sixty cubic meters of contaminated pump oil (including Cs-137, Sr-90 and U-235/238) contained in large above ground tanks had to be treated for final disposal. As a result of the research conducted over a two-year period, a new 2-step treatment process was invented by combining the U.S. solidification technology with a newly developed inorganic filler and molecular sulfur, referred to as radiation-resistant composite (RRC) to fully encapsulate the waste oil. The outcome of extensive test program indicates that the final form can reach up to 60 wt.% with a compressive strength of about 100 kg/cm{sup 2}. Preliminary conclusions indicate that RRC outperforms cement as an encapsulation form for final waste treatment which meets U.S. Nuclear Regulatory requirements for final disposal. This paper examines the preliminary experimental work that was conducted in Kazakhstan with the U.S. polymer technology and radioactive pump oil, and the subsequent secondary process of combining the solidified material into a homogeneous final form utilizing RRC. Topics covered in the paper include: - Kazakhstan's regulatory requirements for attaining an achievable waste form for acceptance, which led to the RRC invention; - Technical objectives for the application of polymer technology and RRC materials to radioactive liquid waste; - Polymer solidification with radioactive oil and the result; step one of the RRC process; - Description of RRC materials, their origin and chemical characteristics; - Process of combining the solidified polymer mass with RRC materials into a solid, homogeneous matrix; step two of the RRC process; - Experimental results including leaching data, waste loading estimates and heat process calculations to create the matrix; - Cost advantages of the RRC process over cementation; - Limitations of the RRC process; - Next steps to verify conformance of the RRC technology to the U.S. requirements. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Immobilization of Radioactive Wastes Using Geopolymers - 19483

This work explores an encapsulation and immobilization technology for spent radioactive ion exchange (IX) resins using geopolymer materials as a matrix. Geopolymer-IX resin composites with different IX resin loadings were prepared by mixing an aluminosilicate material (metakaolin), sodium hydroxide and inactive IX resin (Amberlite IRN 150) and curing the mixture at room temperature with or without γradiation applied using an external radiation source. The metakaolin and sodium hydroxide reacted to form a geopolymer framework encapsulating the IX resin beads. The IX resin loading capacity and the encapsulation efficiency of the geopolymer material were investigated by examining the morphology and distribution of resins within the geopolymer framework using optical microscopy, and by measuring the compressive strengths of the geopolymer-IX resin composites. These properties of the geopolymer-IX resin composites were compared with those of ordinary Portland cement (OPC)-IX resin composites. The geopolymer matrix allowed for a higher IX resin loading capacity than OPC. The geopolymer-IX resin composite was stable under γ-radiation for 28 d. In leaching tests performed with encapsulated Sr-loaded IX resins, the ability of the geopolymer to prevent leaching of Sr{sup 2+} into solution was greatly superior to that of OPC. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2025

SaltStone Wastewater Cement Study Using Isothermal Calorimetry, Standard Concrete Characterization Techniques, and CemGEMS - 25169

Cementitious reagents are used to solidify/stabilize aqueous radioactive, hazardous, and mixed salt solutions, and sludges to meet low-level radioactive waste (LLW) and Resource Conservation and Recovery Act (RCRA) requirements for disposal at Department of Energy (DOE). It is flexible enough to solidify radioactive wastewater saturated in complex species that include but are not limited to radioactive isotopes from the bombardment of neutrons in reactor operation, corrosion products from metallic components, and a variety of soluble organic compounds. [1,2]. Waste form testing typically includes processing or fresh properties, cured properties, compressive strength and hydraulic properties, porosity, density, saturated and unsaturated moisture transport, and leachability of contaminants in the waste form pore solution. Properties are collected over a relatively limited time, typically 28 to 365 days [3]. In addition, changes in the waste form as the result of time and changing conditions are important for concrete engineers to predict overall performance of the forms and potential release of contaminants in the disposal process via unintended filtration into the environment [4]. These predictions are determined/calculated characterizing young waste forms (relative to the standard age of concrete) and are based on transport through soluble ions in pore solutions. Characterization methods include X-ray, SEM, and isothermal calorimetry among other methods used to define the composition, amorphous vs. crystalline nature of the components, and the energetic formation mechanisms for multi-phase mineral systems. [5–7] Isothermal calorimetry is a well standardized technique for cements and concretes and can be used to predict the timing and nature of the hydration reactions.[8] The technique can measure long term energetic

Bustamante, Michael E. [Savannah River National La↗
DOE OSTI2026

Flowable Cementitious Grouts for False Bottoms in Hanford Waste Tanks – 26085

Cementitious grouts with epoxy coatings are being evaluated as an approach to refurbish the bottom of waste tanks at the Hanford Site. This work studies four grout concept materials for this application, two grouts being from commercial vendors and two grouts based off formulations used to close reactors and tanks at the Savannah River Site. All the candidate grouts demonstrate flowability and pumpability at the 0.5 cu ft scale. The commercial vendor products demonstrate the best flow and have lower water/premix ratio and are less likely to have bleed, which would impact epoxy bonding to the grout. The commercial products also demonstrate increased compression strengths compared to the reactor closure grouts. Additional fresh and cured properties for all the grout formulations were similar. The grouts in the tank waste simulant without epoxy coating do not crack but show visual changes to the grout and the surrounding simulant solution, and simulant absorption into the grout. The grout/epoxy bond in ambient conditions has strengths of over 7 MPa and needs to be evaluated for simulant chemical durability. Overall, the results to date justify testing the flowability, pumpability, and placement of the grouts at larger, engineering scale and for further studies of the interactions between the grout and epoxy.

Valdes, Nicholas [Savannah River National Laborato↗
NASA NTRS2024

The Effects of Impactor Shape on the Compression After Impact Strength of Carbon/Epoxy Face Sheet Aluminum Honeycomb Core Sandwich Structure

This study presents experimental results of compression after impact (CAI) strength testing of aluminum core sandwich structure with carbon/epoxy face sheets impacted at three different energies with either a 12.7 mm hemispherical, 24.5 mm hemispherical or sharp tip impactor. This study was undertaken to verify whether design allowables typically generated by blunt (hemispherical) impactors may be valid in ‘real world” applications where an impact may not be by a blunt object of a specific size. Results of practical interest in this study were that the visual damage was much easier to see for the sharp impactor, the damage size as detected by thermography was smaller for the sharp impactor for a given impact energy and dent depth was greater for the sharp impactor. The CAI strength results showed that the sharp impactor gave about the same CAI strength values at all three impact energy levels used. The larger hemispherical impactor gave slightly higher CAI results than the smaller blunt impactor. Overall it was deemed difficult to develop a CAI allowable that would cover all impactor shapes with any fidelity and thus using a lower bound strain allowable is suggested.

compression after impact (CAI)↗
DOE OSTI2020

Using simultaneous x-ray diffraction and velocity interferometry to determine material strength in shock-compressed diamond

We determine the strength of laser shock-compressed polycrystalline diamond at stresses above the Hugoniot elastic limit using a technique combining x-ray diffraction from the Linac Coherent Light Source with velocity interferometry. X-ray diffraction is used to measure lattice strains, and velocity interferometry is used to infer shock and particle velocities. These measurements, combined with density-dependent elastic constants calculated using density functional theory, enable determination of material strength above the Hugoniot elastic limit. Furthermore, our results indicate that diamond retains approximately 20 GPa of strength at longitudinal stresses of 150–300 GPa under shock compression.

36 MATERIALS SCIENCE↗
NASA NTRS2021

Compression After Impact Strength Comparison of Rohacell Foam and Aluminum Honeycomb Core Sandwich Structure

This Technical Memorandum is a follow-on study to a previous one1 that examined the compression after impact (CAI) strength of carbon fiber sandwich structure with aluminum honeycomb core and Rohacell foam core with barely visible impact damage (BVID). In this current study a wider range of impact energies were utilized and the CAI strength assessed with these different damage severity levels. This was done to provide a more complete database for the two types of sandwich structure tested in these studies. In addition, the honeycomb sandwich specimens were tested with both the ‘L’ and ‘W’ directions aligned with the axis of compression loading. As in the study examining CAI strength with BVID1, the results were normalized by the mass of the sandwich structure. The results showed that the CAI strength did differ depending on the orientation of the core during testing and that when tested in the W-direction, the honeycomb core sandwich structure had about the same CAI strength as the foam core sandwich structure when normalized by the mass of the sandwich structures.

Sandwich Structure↗
NASA NTRS2023

The Effects of Off-Axis Loading on the Compression After Impact Strength of Quasi-Isotropic Face Sheet Honeycomb Core Sandwich Structure

This study presents experimental results of compression after impact (CAI) testing of aluminum honeycomb core sandwich structure with face sheets made of co-cured T1100/3960 quasi-isotropic carbon/epoxy when tested at +22.5⁰ and -22.5⁰ with respect to the 0⁰ fibers. In a previous study examining the CAI strengths of honeycomb sandwich structure, it was found that specimens had different CAI strengths, based on a [-45/90/+45/0]s layup, depending on whether they were tested in the 0⁰ direction (face sheet layup of [-45/90/+45/0]s) or 90⁰ direction (face sheet layup of [+45/0/-45/90]s). The CAI strength results showed that the specimens tested in the 90⁰ direction had a 19% drop in CAI strength compared to specimens tested in the 0⁰ direction. This was attributed to the 0⁰ load bearing plies in the 0⁰ direction specimens being “tucked in” at the center of the specimen thus providing more stability against microbuckling. This raised the question as to what CAI strength would specimens tested at +22.5⁰ (face sheet layup of [-22.5/- 67.5/+67.6/+22.5]s) and -22.5⁰ (face sheet layup of [-67.5/+67.5/+22.5/-22.5]s) have compared to specimens tested in the 0⁰ and 90⁰ direction. Results presented in this study show that the specimens loaded at +22.5⁰ and -22.5⁰ have a similar average CAI strength compared to the specimens loaded in the 0⁰ direction. The specimens loaded in the 90⁰ direction exhibit 16% lower average CAI strength. Additional specimens were tested in the +45⁰ direction to put the 0⁰ load bearing fibers on the outside of the specimen to see if this would decrease the strength as has been documented for undamaged strength. These specimens have average CAI strength values between the 0⁰ direction average CAI strength values and the 90⁰ direction average CAI strength values.

Sandwich structure↗
NASA NTRS1999

Parametric Study of Three-Stringer-Panel Compression-After-Impact Strength

Damage tolerance requirements for integrally-stiffened composite wing skins are typically met using design allowables generated by testing impact-damaged subcomponents, such as three-stringer stiffened panels. To improve these structures, it is necessary to evaluate the critical design parameters associated with three-stringer stiffened-panel compressive behavior. During recent research and development programs, four structural parameters were identified as sources for strength variation: (a) material system, (b) stringer configuration, (c) skin layup, and (d) form of axial reinforcement (tape versus pultruded carbon rods). Relative effects of these parameters on damage resistance and damage tolerance were evaluated numerically and experimentally. Material system and geometric configuration had the largest influence on damage resistance; location and extent of the damage zone influenced the sublaminate buckling behavior, failure initiation site, and compressive ultimate strength. A practical global-local modeling technique captured observed experimental behavior and has the potential to identify critical damage sites and estimate failure loads prior to testing. More careful consideration should be given to accurate simulation of boundary conditions in numerical and experimental studies.

Rousseau, Carl Q.↗
NASA NTRS1993

Production of Lunar Concrete Using Molten Sulfur

The United States has made a commitment to go back to the moon to stay in the early part of the next century. In order to achieve this objective it became evident to NASA that a Lunar Outpost will be needed to house scientists and astronauts who will be living on the moon for extended periods of time. A study has been undertaken by the authors and supported by NASA to study the feasibility of using lunar regolith with different binders such as molten sulfur, epoxy or hydraulic cement as a construction material for different lunar structures. The basic premise of this study is that it will be more logical and cost effective to manufacture lunar construction materials utilizing indigenous resources rather than transporting needed materials from earth. Lunar concrete (made from Hydraulic Cement and lunar soil) has been studied and suggested as the construction material of choice for some of the lunar projects. Unfortunately, its hydration requires water which is going to be a precious commodity on the moon. Therefore this study explores the feasibility of using binders other than hydraulic cement such as sulfur or epoxy with lunar regolith as a construction material. This report describes findings of this study which deals specifically with using molten sulfur as a binder for Lunar concrete. It describes laboratory experiments in which the sulfur to lunar soil simulant ratios by weight were varied to study the minimum amount of sulfur required to produce a particular strength. The compressive and tensile strengths of these mixes were evaluated. Metal and fiber glass fibers were added to some of the mixes to study their effects on the compressive and tensile strengths. This report also describes experiments where the sulfur is melted and mixed with the lunar regolith in a specially designed vacuum chamber. The properties of the produced concrete were compared to those of concrete produced under normal pressure.

Omar, Husam A.↗
NASA NTRS2005

Influence of Compression and Shear on the Strength of Composite Laminates With Z-Pinned Reinforcement

The influence of compression and shear loads on the strength of composite laminates with z-pins is evaluated parametrically using a 2D Finite Element Code (FLASH) based on Cosserat couple stress theory. Meshes were generated for three unique combinations of z-pin diameter and density. A laminated plate theory analysis was performed on several layups to determine the bi-axial stresses in the zero degree plies. These stresses, in turn, were used to determine the magnitude of the relative load steps prescribed in the FLASH analyses. Results indicated that increasing pin density was more detrimental to in-plane compression strength than increasing pin diameter. Compression strengths of lamina without z-pins agreed well with a closed form expression derived by Budiansky and Fleck. FLASH results for lamina with z-pins were consistent with the closed form results, and FLASH results without z-pins, if the initial fiber waviness due to z-pin insertion was added to the fiber waviness in the material to yield a total misalignment. Addition of 10% shear to the compression loading significantly reduced the lamina strength compared to pure compression loading. Addition of 50% shear to the compression indicated shear yielding rather than kink band formation as the likely failure mode. Two different stiffener reinforced skin configurations with z-pins, one quasi-isotropic and one orthotropic, were also analyzed. Six unique loading cases ranging from pure compression to compression plus 50% shear were analyzed assuming material fiber waviness misalignment angles of 0, 1, and 2 degrees. Compression strength decreased with increased shear loading for both configurations, with the quasi-isotropic configuration yielding lower strengths than the orthotropic configuration.

OBrien, T. Kevin↗
NASA NTRS2005

Influence of Compression and Shear on the Strength of Composite Laminates with Z-Pinned Reinforcement

The influence of compression and shear loads on the strength of composite laminates with z-pins is evaluated parametrically using a 2D Finite Element Code (FLASH) based on Cosserat couple stress theory. Meshes were generated for three unique combinations of z-pin diameter and density. A laminated plate theory analysis was performed on several layups to determine the bi-axial stresses in the zero degree plies. These stresses, in turn, were used to determine the magnitude of the relative load steps prescribed in the FLASH analyses. Results indicated that increasing pin density was more detrimental to in-plane compression strength than increasing pin diameter. Compression strengths of lamina without z-pins agreed well with a closed form expression derived by Budiansky and Fleck. FLASH results for lamina with z-pins were consistent with the closed form results, and FLASH results without z-pins, if the initial fiber waviness due to z-pin insertion was added to the fiber waviness in the material to yield a total misalignment. Addition of 10% shear to the compression loading significantly reduced the lamina strength compared to pure compression loading. Addition of 50% shear to the compression indicated shear yielding rather than kink band formation as the likely failure mode. Two different stiffener reinforced skin configurations with z-pins, one quaiisotropic and one orthotropic, were also analyzed. Six unique loading cases ranging from pure compression to compression plus 50% shear were analyzed assuming material fiber waviness misalignment angles of 0, 1, and 2 degrees. Compression strength decreased with increased shear loading for both configurations, with the quasi-isotropic configuration yielding lower strengths than the orthotropic configuration.

O'Brien, T. Kevin↗
DOE OSTI2024

Microscale mechanical property variations of Al-substituted LLZO: insights from compression testing and molecular dynamics simulations

Ceramic solid electrolytes based on LLZO (Li 7 La 3 Zr 2 O 12 ) are promising candidates for all-solid-state batteries due to their high ionic conductivity and good apparent stability vs. lithium metal, however they are prone to mechanical failure. Lithium metal intrusions, alongside cell stack pressure, transition polycrystalline solid electrolyte grains into a compressed state that promotes crack propagation and fracture. Here this work examines the mechanical response of Al-substituted LLZO to compressive forces by measuring ultimate strength under pillar compression with a flat punch tip. Failure modes characterized by in situ scanning electron microscopy show diverse splitting patterns arising from internal porosity, grain boundaries, and slip planes. Large correlated variations in compressive strength (0.93–2.63 GPa) and Young's modulus (72.1–150.97 GPa) are observed across microscale regions of the solid electrolyte. Molecular dynamics simulations of LLZO with different porosities describe the variation of compressive strength and Young's modulus, and enable a microscale porosity model to be fit accounting for Young's modulus reduction across the solid electrolyte. Overall, the results indicate the importance of microscale mechanical testing of ceramic solid electrolytes to identify preferential sites for mechanical degradation and Li intrusion, and ensure the robust design of all-solid-state lithium metal batteries.

25 ENERGY STORAGE↗
DOE OSTI2018

Elastic and Plastic Behavior of an Ultrafine-Grained Mg Reinforced with BN Nanoparticles

Pure microcrystalline magnesium (µMg) was reinforced with hexagonal boron nitride (hBN) nanoparticles and was fabricated by powder metallurgy process followed by hot extrusion. For comparison pure magnesium powder was consolidated by hot extrusion too. Both materials exhibited a significant fiber texture. Mg-hBN nanocomposites (nc) and pure Mg specimens were deformed between room temperature and 300 °C under tension and compression mode. The yield strength and ultimate tensile and compression strength as well as characteristic stresses were evaluated and reported. The tensile and compressive strengths of Mg-hBN nc are quiet superior in values compared to monolithic counterpart as well as Mg alloys. The compressive yield strength of µMg was recorded as 90 MPa, whereas the Mg-hBN nancomposite shows 125 MPa at 200 °C. The tensile yield strength of µMg was computed as 67 MPa which is quite lower as compared to Mg-hBN nanocomposite’s value which was recorded as 157 MPa at 200 °C. Under tensile stress the true stress–strain curves are flat in nature, whereas the stress–strain curves observed in compression at temperatures up to 100 °C exhibited small local maxima at the onset of deformation followed by a significant work hardening.

36 MATERIALS SCIENCE↗